Slashdot videos: Now with more Slashdot!

View

Discuss

Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

wjcofkc writes "CNN reports that astronomers using NASA's NuSTAR telescope have for the first time mapped deep within the radioactive material from a supernova. The light from the originating star, Cassiopeia A, located about 11,000 light-years away and having had about eight time the mass of our sun, first reached Earth about 350 years ago. But that does not mean there still isn't a lot to study. Scientists using the NuSTAR, which stands for Nuclear Spectroscopic Telescope Array, launched in June 2012 and consisting of an instrument with two telescopes that focus high energy X-ray light, were able to peer deep within the cataclysmic aftermath. While there is currently no model for how the process of a supernova works, the findings in the study are a big step forward. 'Until we had NuSTAR, we couldn't see down to the core of the explosion,' Brian Grefenstette, lead author and research scientist at the California Institute of Technology, said at a news conference Wednesday."

Universal, no, but physicists agree, and, really, who else matters? X-rays are emitted by electrons (atomic transitions or bremsstrahlung); gamma rays by nuclear transitions. Those definitions have been pretty well agreed upon by physicists for at least the last 15 years.

Astronomers, however, seem to characterize photons only by energy, which kind of makes sense if you realize that they frequently don't know the origin of the observed photons and build instruments for energy ranges instead.

But nonetheless it is still incorrect to characterize these photons as "x-rays."